Fecundity 7 eggs per female over a period of 7 days. Count from the second
day of testing; n = 30 females; an annual test.
Description of testing methods
Quantity Neoseiulus cucumerisis normally sold as a mix of bran, bran mites (as
a food source) and the predatory mites themselves. Both the ratio of
the two mite species and the concentration can vary considerably,
depending on the product and the producer.
Mites can be washed out of the material with (hot) water, though
counting is not easy because of reflection and difficult identification
of the mite species. A more accurate method is to use a ‘Berlese tech-
nique’, as described below. Mites are driven out of the material with
the heat of a lamp. The advantage is that the mite species are clearly
visible and dead mites will remain behind in the sieve. Make sure
that a ‘warming-up time’ is allowed for. This gives the small bran
mites the chance to walk downwards before getting burned. Full
heat is needed to drive the predatory mites out of the sieve.
Use material from one container or four sachets, depending on the
product. Empty the contents into a bucket and weigh the content.
Mix thoroughly with a spoon to get a homogeneous mixture.
According to the density, take the following samples:
Density ofN. cucumeris Sample size1000 5 g^1 0.5 g
500 5 g^1 0.5 g
250 5 g^1 1.0 g
100 5 g^1 1.0 gPut the material directly in a sieve of 6 cm diameter, 2.5 cm height,
mesh width 333μm, 42% open. Spread the material as evenly as pos-
sible. Place the sieve at a distance of 4 cm under a lamp of 150 W. The
warming-up time should take 5 min. Full power for an extra 10 min
(see Figs 19.9 and 19.10). Put a piece of black sticky tape under the
sieve to trap the falling mites.
The number of mites can be counted directly with a grid or if the
mites can still walk over the glue, they can be killed in the freezer (20
min). Use fibre light to prevent melting of the glue. The stickiness of
the glue is very important. When the tape is not sticky many mites
will walk off the tape.
An alternative for the black sticky tape is to use a black plate with
a ring of pure detergent as a barrier. Mites must be killed in the
freezer immediately after extracting them. The humidity of the mate-
rial is also very important. Within the range of 16.5–19% there does
not seem to be a difference in the counting. At a higher humidity of
the material, there may be a different total heating time, because
mites stay longer in the material.
Fecundity
Day 0 The test is conducted on individual female mites in small round plas-
tic Petri-dish trays (32 mm diameter; 15 mm height), which can be
closed tightly. A nylon mesh is incorporated into the lid for ventila-
tion. Trays are filled with agar solution (1%) to a depth of 5 mm. Just
Quality Control Guidelines for Biocontrol Agents 293